1. Field of the Invention
The invention relates to installation of insulation, particularly to installation of high temperature, fragile fibrous insulation in restricted space.
2. Description of the Prior Art
There is no known prior art dealing with the specific problem, which arose in connection with the development of heat resistant seals for aerospace vehicles subject to surface heating. Such heating can produce very high temperatures, well beyond the temperatures at which ordinary seal materials are destroyed or very adversely affected. Accordingly, ceramic fiber insulation materials available as batting are used. These materials are relatively fragile, however, and consequently cannot be installed in, or pulled into, restricted spaces without mechanically damaging them and destroying the uniformity of their insulation qualities.
Application of insulation for one purpose or another is, of course, known in the prior art. U.S. Pat. No. 3,922,425 discloses a material useful in roofing, in which a thermal insulation composition is enclosed in a plastic film which is dissolved by hot asphalt applied during a roofing operation. No disclosure concerning emplacement of insulation in restricted spaces is included, however.
U.S. Pat. No. 2,304,233 discloses a method of insulating double-wall panels (i.e., refrigerator doors, etc.) to prevent "slump" or displacement during use. Again the problem of insulation placement in restricted spaces is not addressed.
Another U.S. Pat. No. 3,546,846 deals with the packaging of insulation material. This method may be considered to be relevant to the plastic film enclosing step of the present invention, but does not address the restricted space installation problem, nor does it disclose the concept of using a fugitive packaging material for handling and installation purposes and later evolving that material by baking.
It has been recognized that an effective high heat seal for doors, exterior panels and the like on aerospace vehicles can be produced as an elongated assembly comprising a spring wire mesh sleeve with a high temperature fibrous insulation therein. Such insulation materials are mineral fiber or ceramic types, having very low mechanical strength preventing their being pulled or drawn, especially through elongated restricted spaces.
The manner in which the method of the invention deals with this problem will be understood as this description proceeds.